This invention concerns a process for encoding printed circuit boards to detect automatically at least two population variants of these printed circuit boards for a production run comprising several population processes to populate printed circuit boards with electronic and non-electronic components.
Frequently, in industrial manufacturing of electronic assemblies, different variants with special or auxiliary functions are produced, and the associated printed circuit boards differ then in that they all feature different populations, leading to a certain number of population variants. To save on costs in the production process, there is an attempt to cover this great variety of variants by using just one basic printed circuit board. However, the problem then is that the automatic populating machine must itself now detect these various population variants at each production step. There is a danger of possible mix-ups during the production run.
It is well known that in order to uniquely identify printed circuit boards with regard to their different population variants, stick-on labels or bar codes are used; however, this involves additional labour and material costs, and thus gives rise to additional production costs. For printed circuit boards populated on both sides, there is the additional problem that such stick-on labels or bar codes will be readable from one side only.